Taking the stand for the first time on Monday, former Central Narcotics Bureau chief Ng Boon Gay described some 30 sexual encounters with Ms Cecilia Sue at spots around Singapore - all of which he claimed were consensual.
Ng said he was having an "extra-marital affair" with the married IT sales executive from 2009 until the end of 2011. In the context of this relationship, they had engaged in "hugging", "kissing", "petting" and "oral sex", he said in court.
Ng took the stand after District Judge Siva Shanmugam ruled on Monday that he had a case to answer.
He faces four counts of obtaining oral sex from Ms Sue last year in exchange for furthering the business interests of her then-employers Hitachi Data Systems and Oracle Corporation Singapore.
Earlier in the day, the prosecution said that the evidence produced in court so far showed that Ng had obtained oral sex from Ms Sue, knowing that she was seeking contracts with the agency which he headed, and that there was a corrupt element in those transactions.
But Ng's lawyer Tan Chee Meng argued that since his client and Ms Sue were in an intimate relationship at the time of the sexual encounters, the acts were given in the context of the relationship, and did not amount to gratification.